Handling Emergencies

Study questions with answers

6 sample Handling Emergencies questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.

1. 1. After a loss of air, why does a heavily loaded vehicle need a long distance to stop once the spring brakes apply?

   Correct answer: The spring brakes act on only some of the axles

   Spring brakes act on only some axles, so a heavy load takes a long way to stop; it is far safer to pull over while there is still air for the foot brakes.

   Source: Section 5.4.7 - Low Air Pressure

2. 2. In "controlled braking" during an emergency, how hard do you apply the brakes?

   Correct answer: As hard as possible without letting the wheels lock

   Controlled braking means braking as hard as you can while keeping the wheels turning and steering movements small; if a wheel locks or you must steer more, ease off then reapply.

   Source: Section 5.4.3 - Emergency Stops

3. 3. Using the proper downhill braking technique, how long should each brake application last?

   Correct answer: About three seconds

   Once in a low gear, brake hard enough to feel a clear slowdown for roughly three seconds, dropping about five mph below your safe speed, then release.

   Source: Section 5.4.6 - Proper Braking Technique

4. 4. Describe the "stab braking" method for an emergency stop.

   Correct answer: Fully apply the brakes, release when the wheels lock, then reapply fully once they roll

   Stab braking means pressing the brakes all the way, releasing the instant the wheels lock, then reapplying fully once they roll again, allowing up to a second for that.

   Source: Section 5.4.3 - Emergency Stops

5. 5. If only the tractor of a combination has ABS and the trailer starts to swing out, what should you do?

   Correct answer: Ease off the brakes if you can do so safely

   With ABS on the tractor only you keep steering control, but watch the trailer and let up on the brakes, when it is safe, if it begins to swing out.

   Source: Section 5.4.2 - Braking with Antilock Brakes

6. 6. On a tractor or straight truck, spring brakes come fully on when air pressure drops into what range?

   Correct answer: 20 to 45 psi

   The springs apply fully as pressure falls to somewhere between 20 and 45 psi (often 20 to 30); do not wait for this and instead stop safely when the low-air warning first appears.

   Source: Section 5.1.14 - Spring Brakes